Upgraded polyethylene for jacketing

ABSTRACT

Mixed-plastic-polyethylene composition having a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.1 to 0.9 g/10 min; and a density of from 956 kg/m 3  to 970 kg/m 3 , preferably from 958 to 968 kg/m 3 .

FIELD OF THE INVENTION

The present invention relates to upgrading of PE recycling streams usingvirgin high-density polyethylenes (HDPE) to give jacketing materialsthat have acceptable ESCR (Environmental Stress Crack Resistance)performance.

BACKGROUND

Polyolefins, in particular polyethylene and polypropylene areincreasingly consumed in large amounts in a wide range of applications,including packaging for food and other goods, fibres, automotivecomponents, and a great variety of manufactured articles.

Polyethylene based materials are a particular problem as these materialsare extensively used in packaging. Taking into account the huge amountof waste collected compared to the amount of waste recycled back intothe stream, there is still a great potential for intelligent reuse ofplastic waste streams and for mechanical recycling of plastic wastes.

Generally, recycled quantities of polypropylene on the market aremixtures of both polypropylene (PP) and polyethylene (PE), this isespecially true for post-consumer waste streams. Moreover, commercialrecyclates from post-consumer waste sources are conventionally crosscontaminated with non-polyolefin materials, such as polyethyleneterephthalate, polyamide, polystyrene or non-polymeric substances likewood, paper, glass or aluminium. These cross-contaminations drasticallylimit final applications or recycling streams such that no profitablefinal uses remain.

In addition, recycled polyolefin materials normally have properties,which are much worse than those of the virgin materials, unless theamount of recycled polyolefin added to the final compound is extremelylow. For example, such materials often have limited impact strength andpoor mechanical properties (such as e.g. brittleness) and thus, they donot fulfil customer requirements. For several applications, e.g.jacketing materials (for cables), containers, automotive components orhousehold articles. This normally excludes the application of recycledmaterials for high quality parts, and means that they are only used inlow-cost, non-demanding applications, such as e.g. in construction or infurniture. In order to improve the mechanical properties of theserecycled materials, generally relatively large amounts of virginmaterials (produced from oil) are added.

U.S. Pat. No. 8,981,007 B2 relates to non-crosslinked polyethylenecompositions for use in the jacketing of power cables. Generallycrosslinked polyethylene is used for power cables, due to its excellentheat resistance, chemical resistance and electrical properties. However,since crosslinked polyethylene resin is a thermoset resin, it is notrecyclable. There is, therefore, a demand for an eco-friendlynon-crosslinked type thermoplastic polyethylene resin, which is alsoheat resistant and hence suitable for use in power cables.

EP 2417194 B1 also relates to uncrosslinked polyethylene compositionsfor use in power cables. The compositions disclosed herein are polymerblends comprising MDPE and HDPE and one or more additive(s) selectedfrom a flame retardant, an oxidation stabilizer, a UV stabilizer, a heatstabilizer and a process aid.

DE-102011108823-A1 relates to a composite for the electrical isolationof electrical cables. The composite comprises a plastic, a materialhaving a heat conductivity of less than 1 W/(mk) and a displacementmaterial (C). In certain embodiments, the displacement material can be arecycled material.

EP 1676283 B1 relates to medium/high voltage electrical energy transportor distribution cables comprising at least one transmissive element andat least one coating layer, said coating layer being made from a coatingmaterial comprising at least one recycled polyethylene (obtained from awaste material) with a density not higher than 0.940 g/cm³ and at leasta second polyethylene material having a density higher than 0.940 g/cm³.The coating material in some of the examples of EP 1676283 B1 showedimproved values with respect to stress cracking resistance with respectto those obtained from recycled polyethylene alone. However, thesevalues were considerably lower than those obtained with the virginmaterial.

A particular problem in recycled polyethylene materials is that ESCR(Environmental Stress Crack Resistance) properties are unacceptabledepending on the waste origin. ESCR can be evaluated with a number ofparameters including the failure time of Bell test and strain hardeningmodulus, i.e., the slope of the strain hardening part of a stress-straincurve (Kurelec, L.; Teeuwen, M.; Schoffeleers, H.; Deblieck, R., Strainhardening modulus as a measure of environmental stress crack resistanceof high density polyethylene. Polymer 2005, 46 (17), 6369-6379). Thus,there is need for addressing these limitations in a flexible way. Forjacketing applications an ESCR Bell test failure time of >1000 hours isdesirable. In addition to that there is usually a problem with tensilestrain at break (in %). Materials made from recycling streams usuallysuffer from very low tensile strain at break values, whereby the end-useapplications are severely limited.

Thus, there remains a need in the art to provide recycled polyethylenesolutions for jacketing materials that have acceptable and constant ESCR(Environmental Stress Crack Resistance) performance, with Bell testfailure time>1000 hours, preferably >2000 hours with other properties,particularly tensile properties, especially tensile strain at break, aswell as acceptable or even good strain hardening modulus which aresimilar to blends of virgin polyethylene and carbon black marketed forthe purpose of cable jacketing.

SUMMARY OF THE INVENTION

In the broadest aspect the present invention provides

A mixed-plastic-polyethylene composition

-   -   comprising a mixed-plastic-polyethylene primary recycling blend        (A), the mixed-plastic-polyethylene composition    -   having        -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.1 to            0.9 g/10 min;        -   a density of from 956 kg/m³ to 970 kg/m³;    -   the mixed-plastic-polyethylene composition comprising    -   a total amount of ethylene units (C2 units) of from 90.0 to 95        wt.-%, preferably 90.0 to 93.3 wt.-%, and    -   a total amount of continuous units having 3 carbon atoms        corresponding to polypropylene (continuous C3 units) of from 4.0        to 8.0 wt.-%, preferably 5.5 to 6.5 wt.-%,    -   a total amount of units having 4 carbon atoms (C4 units) of from        1.00 to 2.00 wt.-%, preferably 1.20 wt.-% to 1.40 wt.-%;    -   with the total amounts of C2 units, continuous C3 units and        units having 4 carbon atoms being based on the total weight        amount of monomer units in the composition and measured        according to quantitative ¹³C{¹H} NMR measurement.

The present invention is based on the surprising finding that a goodESCR and strain hardening performance is obtained when

-   -   the total amount of units having 4 carbon atoms (C4 units) is        from 1.00 wt.-% to 2.00 wt.-%, particularly 1.0 to 1.40 wt.-%        measured according to quantitative ¹³C{¹H} NMR measurement, and        when simultaneously    -   the total amount of continuous units having 3 carbon atoms        corresponding to polypropylene (continuous C3 units) is from 4.0        to 8.0 wt.-%, particularly 5.5 to 6.5 wt. %.

The present invention provides a compositions with excellent ESCRperformance (Bell test failure time>1000 hours, preferably >2000 hours)and good strain hardening range, while maintaining other propertiessimilar to blends of virgin polyethylene and carbon black marketed forthe purpose of cable jacketing.

The mixed-plastic-polyethylene composition is obtainable by blending andextruding

-   -   10.0 to 70.0 wt.-% of a mixed-plastic-polyethylene primary        recycling blend (A) wherein 90.0 wt.-%, preferably 95.0 wt.-%,        more preferably 100.0 wt.-% of the mixed-plastic-polyethylene        primary blend (A) originates from post-consumer waste having a        limonene content of from 0.10 to 500 ppm; and        -   wherein the mixed-plastic-polyethylene primary blend (A) has            -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from                0.1 to 1.5 g/10 min, preferably from 0.4 to 1.3 g/10                min;            -   a density of from 945 to 990 kg/m³;            -   optionally a shear thinning index SHI_(2.7/210) of 30 to                60, preferably 35 to 50            -   optionally a polydispersity index from 1.2 to 2.5 s⁻¹,                more preferably 1.6 to 2.2 s⁻¹ as obtained from                rheological measurement;            -   and a content of units derived from ethylene of 70.0 to                95.0 wt.-% as determined by quantitative ¹³C{¹H}-NMR;    -   25.0 to 88.0 wt.-% of a secondary component (B) being a first        virgin high-density polyethylene (HDPE1) optionally blended with        carbon black, the secondary component (B) having        -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.1 to            1.2 g/10 min, preferably from 0.2 to 0.6 g/10 min;        -   a density of from 940 to 970 kg/m³, preferably from 955 to            970 kg/m³;        -   a shear thinning index SHI_(2.7/210) of 15 to 30;        -   a polydispersity index from 1.6 to 2.2 s⁻¹ as obtained from            rheological measurement;        -   optionally a carbon black content of 1.5 to 3.0 wt.-% with            respect to the secondary component (B); and        -   preferably a limonene content below 0.10 ppm, and    -   2.0 to 20.0 wt.-% of a second virgin high-density        polyethylene (C) having        -   a melt flow rate (ISO 1133, 5.0 kg, 190° C.) of from 0.05 to            1.0 g/10 min, preferably from 0.05 to 0.7 g/10 min, more            preferably from 0.10 to 0.5 g/10 min;        -   a density from 945 to 965 kg/m³,        -   polydispersity index from 2.2 to 4.0 s⁻¹ as obtained from            rheological measurement; and        -   preferably a limonene content below 0.10 ppm.

The invention is further directed to an article, comprising themixed-plastic-polyethylene composition of the present invention,preferably wherein the article is a cable jacket.

Also provided is a process for preparing the mixed-plastic-polyethylenecomposition of the invention, comprising the steps of:

-   -   a. providing a mixed-plastic-polyethylene primary recycling        blend (A) in an amount of 10.0 to 70.0 wt.-% based on the        overall weight of the composition,        -   wherein 90.0 wt.-%, preferably 95.0 wt.-%, more preferably            100.0 wt.-% of the mixed-plastic-polyethylene primary            blend (A) originates from post-consumer waste having a            limonene content of from 0.10 to 500 ppm and wherein the            mixed-plastic-polyethylene primary blend has        -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.1 to            1.5 g/10 min, preferably from 0.4 to 1.3 g/10 min;        -   a density of from 945 to 990 kg/m³;        -   preferably a shear thinning index SHI_(2.7/210) of 30 to 60,            more preferably from 35 to 50;        -   preferably a polydispersity index from 1.2 to 2.5 s⁻¹, more            preferably from 1.6 to 2.2 s⁻¹ as obtained from rheological            measurement,        -   and a content of units derived from ethylene of 70.0 to 95.0            wt.-% as determined by quantitative ¹³C{¹H}-NMR,    -   b. providing a secondary component (B) being a virgin        high-density polyethylene (HDPE1) optionally blended with carbon        black, in an amount of 25.0 to 88.0 wt.-% based on the overall        weight of the composition, the secondary component (B) having        -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.1 to            1.2 g/10 min, preferably from 0.2 to 0.6 g/10 min;        -   a density of from 940 to 970 kg/m³, preferably from 955 to            970 kg/m³,        -   a shear thinning index SHI_(2.7/210) of 15 to 30        -   a polydispersity index from 1.6 to 2.2 s⁻¹ as obtained from            rheological measurement,        -   optionally a carbon black content of 1.5 to 3.0 wt.-% with            respect to the secondary component (B); and        -   preferably a limonene content below 0.10 ppm,    -   c. 2.0 to 20.0 wt.-% of a second virgin high-density        polyethylene (C) having        -   a melt flow rate (ISO 1133, 5.0 kg, 190° C.) of from 0.05 to            1.0 g/10 min, preferably from 0.05 to 0.7 g/10 min, more            preferably from 0.10 to 0.5 g/10 min;        -   a density from 945 to 965 kg/m³,        -   polydispersity index from 2.2 to 4.0 s⁻¹ as obtained from            rheological measurement; and        -   preferably a limonene content below 0.10 ppm.    -   d. melting and mixing the blend of mixed-plastic-polyethylene        primary blend (A), the secondary component (B) and the second        virgin high-density polyethylene (C) in an extruder, optionally        a twin screw extruder, and    -   e. optionally pelletizing the obtained        mixed-plastic-polyethylene composition.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which the invention pertains. Although, any methods andmaterials similar or equivalent to those described herein can be used inpractice for testing of the present invention, the preferred materialsand methods are described herein. In describing and claiming the presentinvention, the following terminology will be used in accordance with thedefinitions set out below.

Unless clearly indicated otherwise, use of the terms “a,” “an,” and thelike refers to one or more.

For the purposes of the present description and of the subsequentclaims, the term “recycled waste” is used to indicate a materialrecovered from both post-consumer waste, as opposed to virgin polymersand/or materials. Post-consumer waste refers to objects having completedat least a first use cycle (or life cycle), i.e. having already servedtheir first purpose.

The term “virgin” denotes the newly produced materials and/or objectsprior to their first use, which have not already been recycled. The term“recycled material” such as used herein denotes materials reprocessedfrom “recycled waste”.

The term “natural” in the context of the present invention means thatthe components are of natural colour. This means that no pigments(including carbon black) are included in the components of themixed-plastic-polyethylene composition of the present invention.

A blend denotes a mixture of two or more components, wherein one of thecomponents is polymeric. In general, the blend can be prepared by mixingthe two or more components. Suitable mixing procedures are known in theart. The secondary component (B) may be a blend comprising at least 90wt.-% of a reactor made high density polyethylene material, as well ascarbon black. This high density polyethylene material is a virginmaterial which has not already been recycled.

For the purposes of the present description and of the subsequentclaims, the term “mixed-plastic-polyethylene” indicates a polymermaterial including predominantly units derived from ethylene apart fromother polymeric ingredients of arbitrary nature. Such polymericingredients may for example originate from monomer units derived fromalpha olefins such as propylene, butylene, octene, and the like, styrenederivatives such as vinylstyrene, substituted and unsubstitutedacrylates, substituted and unsubstituted methacrylates.

Said polymeric materials can be identified in the mixed-plasticpolyethylene composition by means of quantitative ¹³C{¹H} NMRmeasurements as described herein. In the quantitative ¹³C{¹H} NMRmeasurement used herein and described below in the measurement methodsdifferent units in the polymeric chain can be distinguished andquantified. These units are ethylene units (C2 units), units having 3, 4and 6 carbons and units having 7 carbon atoms.

Thereby, the units having 3 carbon atoms (C3 units) can be distinguishedin the NMR spectrum as isolated C3 units (isolated C3 units) and ascontinuous C3 units (continuous C3 units) which indicate that thepolymeric material contains a propylene based polymer. These continuousC3 units can also be identified as iPP units. The continuous C3 unitsthereby can be distinctively attributed to themixed-plastic-polyethylene primary recycling blend (A) as the secondarycomponent (B) and the second virgin high-density polyethylene (C) in themixed-plastic-polyethylene composition according to the presentinvention usually does not include any propylene based polymericcomponents.

The units having 3, 4, 6 and 7 carbon atoms describe units in the NMRspectrum which are derived from two carbon atoms in the main chain ofthe polymer and a short side chain or branch of 1 carbon atom (isolatedC3 unit), 2 carbon atoms (C4 units), 4 carbon atoms (C6 units) or 5carbon atoms (C7 units).

The units having 3, 4 and 6 carbon atoms (isolated C3, C4 and C6 units)can derive either from incorporated comonomers (propylene, 1-butene and1-hexene comonomers) or from short chain branches formed by radicalpolymerization.

The units having 7 carbon atoms (C7 units) can be distinctivelyattributed to LDPE contamination in recycling polyethylene streams. InLDPE resins the amount of C7 units is always in a distinct range. Thus,the amount of C7 units measured by quantitative ¹³C{¹H} NMR measurementscan be used to calculate the amount of LDPE in a polyethylenecomposition.

Thus, the amounts of continuous C3 units, isolated C3 units, C4 units,C6 units and C7 units are measured by quantitative ¹³C{¹H} NMRmeasurements as described below, whereas the amount of LDPE can becalculated from the amount of C7 units as described below.

The total amount of ethylene units (C2 units) is attributed to units inthe polymer chain, which do not have short side chains of 1-5 carbonatoms, in addition to the units attributed to the LDPE (i.e. units whichhave longer side chains branches of 6 or more carbon atoms).

A mixed-plastic-polyethylene primary recycling blend (A) denotes thestarting primary blend containing the mixed plastic-polyethylene asdescribed above. Conventionally further components such as filers,including organic and inorganic fillers for example talc, chalk, carbonblack, and further pigments such as TiO₂ as well as paper and cellulosemay be present. According to the present invention, the waste stream isa consumer waste stream, such a waste stream may originate fromconventional collecting systems such as those implemented in theEuropean Union. Post-consumer waste material is characterized by alimonene content of from 0.10 to 500 ppm (as determined using solidphase microextraction (HS-SPME-GC-MS) by standard addition).

Mixed-plastic-polyethylene primary blend(s) (A) as used herein arecommercially available. Suitable blends include a number of recyclatesavailable from Mtm plastics under the brand name Purpolen.

Within the meaning of this invention the term “jacketing materials”refers to materials used in cable jacketing/cable coating applicationsfor electrical/telephone/telecommunications cables. These materials arerequired to show good ESCR properties, such as a Bell test failure timeof >1000 hours.

If not indicated otherwise “%” refers to weight-%.

DETAILED DESCRIPTION

Natural Mixed-Plastic-Polyethylene Primary Recycling Blend (A)

The mixed-plastic-polyethylene composition according to the presentinvention comprises a mixed-plastic-polyethylene primary recycling blend(A). It is the essence of the present invention that this primaryrecycling blend is obtained from a post-consumer waste stream.

According to the present invention the mixed-plastic-polyethyleneprimary recycling blend (A) is generally a blend, wherein at least 90.0wt.-%, preferably at least 95.0 wt.-%, more preferably 100.0 wt.-% ofthe mixed-plastic-polyethylene primary blend originates frompost-consumer waste, such as from conventional collecting systems(curb-side collection), such as those implemented in the European Union.

Said post-consumer waste can be identified by its limonene content. Itis preferred that the post-consumer waste has a limonene content of from0.10 to 500 ppm.

The mixed-plastic-polyethylene primary recycling blend (A) preferablycomprises a total amount of ethylene units (C2 units) of from 70.0 wt.-%to 95.0 wt.-%, more preferably of from 71.5 wt.-% to 92.0 wt.-%, stillmore preferably of from 73.0 wt.-% to 90.0 wt.-% and most preferably offrom 74.0 wt.-% to 88.0 wt.-%.

The total amounts of C2 units are based on the total weight amount ofmonomer units in the mixed-plastic-polyethylene primary recycling blend(A) and are measured according to quantitative ¹³C{1 H} NMR measurement.

The mixed-plastic-polyethylene primary recycling blend (A) preferablyfurther comprises a total amount of continuous units having 3 carbonatoms corresponding to polypropylene (continuous C3 units) of from 4.0to 30.0 wt.-%, more preferably from 7.0 wt.-% to 28.0 wt.-%, still morepreferably from 9.0 wt.-% to 26.5 wt.-% and most preferably from 11.0wt.-% to 25.5 wt.-%.

In addition to C2 units and continuous C3 units themixed-plastic-polyethylene primary recycling blend (A) can furthercomprise units having 3, 4, 6 or 7 or more carbon atoms so that themixed-plastic-polyethylene primary recycling blend (A) overall cancomprise ethylene units and a mix of units having 3, 4, 6 and 7 or morecarbon atoms.

The mixed-plastic-polyethylene primary recycling blend (A) preferablycomprises one or more in any combination, preferably all of:

-   -   a total amount of units having 3 carbon atoms as isolated C3        units (isolated C3 units) of from 0.01 wt.-% to 0.50 wt.-%, more        preferably from 0.05 wt.-% to 0.45 wt.-%, still more preferably        from 0.10 wt.-% to 0.40 wt.-% and most preferably from 0.15        wt.-% to 0.35 wt.-%;    -   a total amount of units having 4 carbon atoms (C4 units) of from        0.01 to 0.60 wt.-%, more preferably from 0.05 wt.-% to 0.50        wt.-%, still more preferably from 0.10 wt.-% to 0.45 wt.-% and        most preferably from 0.20 wt.-% to 0.40 wt.-%;    -   a total amount of units having 6 carbon atoms (C6 units) of from        0.01 to 1.00 wt.-%, more preferably from 0.05 wt.-% to 0.80        wt.-%, still more preferably from 0.10 wt.-% to 0.60 wt.-% and        most preferably from 0.15 wt.-% to 0.50 wt.-%; and    -   a total amount of units having 7 carbon atoms (C7 units) of from        0.00 wt.-% to 0.50 wt.-%, of from 0.00 wt.-% to 0.20 wt.-%,        still more preferably of from 0.00 to 0.10 wt.-% yet more        preferably of from 0.00 wt.-% to 0.05 wt.-%, most preferably        there are is no measureable content of units having 7 carbon        atoms (C7 units).

The total amounts of C2 units, continuous C3 units, isolated C3 units,C4 units, C6 units and C7 units thereby are based on the total weightamount of monomer units in the mixed-plastic-polyethylene primaryrecycling blend (A) and are measured or calculated according toquantitative ¹³C{1 H} NMR measurement.

Preferably, the total amount of units, which can be attributed tocomonomers (i.e. isolated C3 units, C4 units, C6 units and C7 units), inthe mixed-plastic-polyethylene primary recycling blend (A) is from 0.10wt.-% to 2.00 wt.-%, more preferably from 0.20 wt.-% to 1.70 wt.-%,still more preferably from 0.25 wt.-% to 1.40 wt.-% and most preferablyfrom 0.30 wt.-% to 1.20 wt.-%, and is measured according to quantitative¹³C{¹H} NMR measurement.

It is preferred that the mixed-plastic-polyethylene primary recyclingblend (A) has

-   -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.1 to 1.2        g/10 min, more preferably from 0.5 to 1.0 g/10 min; and/or    -   a density of from 945 to 990 kg/m³, more preferably from 948 to        987 kg/m³, most preferably from 950 to 985 kg/m³.

The mixed-plastic-polyethylene primary recycling blend (A) may alsoinclude:

-   -   a) 0 to 10.0 wt.-% units derived from olefin(s) comprising        functional groups,    -   b) 0 to 3.0 wt.-% stabilizers,    -   c) 0 to 3.0 wt.-% talc,    -   d) 0 to 3.0 wt.-% chalk,    -   e) 0 to 3.0 wt.-% TiO₂, and    -   f) 0 to 6.0 wt.-% further components        all percentages with respect to the mixed-plastic-polyethylene        primary recycling blend (A).

The mixed-plastic-polyethylene primary recycling blend (A) preferablyhas one or more, more preferably all, of the following properties in anycombination:

-   -   a melt flow rate (ISO 1133, 5.0 kg, 190° C.) of from 2.0 to 6.0        g/10 min, more preferably from 3.0 to 5.0 g/10 min;    -   a melt flow rate (ISO 1133, 21.6 kg, 190° C.) of from 50.0 to        120.0 g/10 min, more preferably from 70.0 to 100.0 g/10 min;    -   a polydispersity index PI of from 1.2 to 2.5 s⁻¹, more        preferably from 1.6 to 2.2 s⁻¹, yet more preferably from 1.7 to        2.1 s⁻¹;    -   a shear thinning index SHI_(2.7/210) of from 30 to 60, more        preferably 35 to 50, yet more preferably from 38 to 47;    -   a complex viscosity at the frequency of 300 rad/s, eta₃₀₀, of        from 450 to 700 Pa·s, more preferably from 500 to 650 Pa·s;    -   a complex viscosity at the frequency of 0.05 rad/s, eta_(0.05),        of from 20000 to 40000 Pa·s, more preferably from 25000 to 35000        Pa·s;    -   a xylene hot insoluble content, XHU, of from 0.01 to 1.0 wt.-%,        more preferably from 0.1 to 0.5 wt.-%, and/or    -   a limonene content of from 0.10 to 500 ppm.

Generally, recycled materials perform less well in functional tests suchas the ESCR (Bell test failure time), SH modulus and Shore D tests thanvirgin materials or blends comprising virgin materials. Usually ESCR(Bell test failure time) of recycled materials is extremely low, andfrequently not measurable at all with the standard test (completefailure).

The mixed-plastic-polyethylene primary recycling blend (A) is preferablypresent in the composition of the present invention in an amount of from10.0 to 70.0 wt.-%, more preferably 10.0 to 60.0 wt.-%, still morepreferably from 15.0 to 50.0 wt.-%, and most preferably from 20.0 to45.0 wt.-%, based on the overall weight of the composition.

Secondary Component (B)

The mixed-plastic-polyethylene composition of the invention comprises asecondary component (B) being a virgin high-density polyethylene (HDPE1)optionally blended with carbon black (CB).

The secondary component (B) preferably has:

-   -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.1 to 1.2        g/10 min, preferably from 0.2 to 0.6 g/10 min; and/or    -   a density of from 940 to 970 kg/m³, more preferably 955 to 970        kg/m³, et more preferably from 959 to 967 kg/m³; and/or    -   a polydispersity index from 1.6 to 2.2 s⁻¹, more preferably from        1.8 to 2.1 s⁻¹,    -   a shear thinning index SHI_(2.7/210) of 15 to 30, more        preferably 20 to 27,    -   optionally a carbon black content of 1.5 to 3.0 wt.-%, with        respect to the secondary component (B), more preferably of 1.8        to 2.8 wt.-%, and    -   a limonene content below 0.10 ppm.

The secondary component (B) includes as polymeric component a copolymerof ethylene and one or more comonomer units selected from alpha-olefinshaving from 3 to 6 carbon atoms. It is preferred that the polymericcomponent is a copolymer of ethylene and 1-butene or a copolymer ofethylene and 1-hexene.

Apart from the polymeric component the secondary component (B) canfurther comprise additives in an amount of 10 wt.-% or below, morepreferably 9 wt.-% or below, more preferably 7 wt.-% or below of thesecondary component (B). Suitable additives are usual additives forutilization with polyolefins, such as stabilizers (e.g. antioxidantagents), metal scavengers and/or UV-stabilizers, antistatic agents andutilization agents (such as processing aid agents).

The secondary component (B) preferably has one or more, more preferablyall of the following properties in any combination:

-   -   a melt flow rate (ISO 1133, 5.0 kg, 190° C.) of from 1.0 to 5.0        g/10 min, more preferably from 1.3 to 3.0 g/10 min;    -   a melt flow rate (ISO 1133, 21.6 kg, 190° C.) of from 20.0 to        50.0 g/10 min, more preferably from 25.0 to 40.0 g/10 min;    -   a complex viscosity at the frequency of 300 rad/s, eta₃₀₀, of        from 500 to 900 Pa·s, more preferably from 600 to 850 Pa·s;    -   a complex viscosity at the frequency of 0.05 rad/s, eta_(0.05),        of from 15000 to 30000 Pa·s, more preferably from 17500 to 27500        Pa·s;    -   a Shore D hardness, measured after 15 s according to ISO 868,        Shore D 15 s, of from 50.0 to 70.0, more preferably of from 55.0        to 65.0,    -   a Shore D hardness, measured after 1 s according to ISO 868,        Shore D 1 s, of from 55.0 to 75.0, more preferably of from 58.0        to 70.0,    -   a Shore D hardness, measured after 3 s according to ISO 868,        Shore D 3 s, of from 55.0 to 75.0, more preferably of from 58.0        to 70.0,    -   a strain hardening modulus, SH modulus, of from 20.0 to 35.0        MPa, more preferably from 22.5 to 32.5 MPa,    -   a Charpy notched impact strength at 23° C., Charpy NIS 23° C.,        of from 8.0 to 20.0 kJ/m², more preferably from 10.0 to 17.5        kJ/m²,    -   a Charpy notched impact strength at 0° C., Charpy NIS 0° C., of        from 4.0 to 15.0 kJ/m², more preferably from 6.0 to 12.5 kJ/m²,    -   a tensile stress at break of from 25 to 50 MPa, more preferably        from 28 to 40 MPa,    -   a tensile strain at break of from 700 to 1000%, more preferably        from 800 to 950%,    -   an environmental stress crack resistance, ESCR, of at least 2500        hours, more preferably at least 3000 hours.

Generally, recycled materials perform less well in functional tests suchas the ESCR (Bell test failure time), SH modulus and Shore D tests thanvirgin materials or blends comprising virgin materials.

The secondary component (B) is preferably present in the composition ofthe present invention in an amount of from 25.0 to 88.0 wt.-%, morepreferably 35.0 to 85.0 wt.-%, still more preferably from 45.0 to 80.0wt.-%, and most preferably from 50.0 to 75.0 wt.-%, based on the overallweight of the composition.

The secondary component (B) preferably contains carbon black in andamount of 1.5 to 3.0 wt.-%, with respect to the secondary component (B),more preferably of 1.8 to 2.8 wt.-% and most preferably 2.0 to 2.8wt.-%.

Second Virgin High-Density Polyethylene (C)

The mixed-plastic-polyethylene composition of the invention comprises asecond virgin high-density polyethylene (C).

The second virgin high-density polyethylene (C) preferably has one ormore, more preferably all of the following properties in any combination

-   -   a melt flow rate (ISO 1133, 5.0 kg, 190° C.) of from 0.05 to 1.0        g/10 min, preferably from 0.05 to 0.7 g/10 min, more preferably        from 0.10 to 0.5 g/10 min;    -   a density from 945 to 965 kg/m³;    -   a polydispersity index from 2.2 to 4.0 s⁻¹ as obtained from        rheological measurement; and/or    -   a limonene content below 0.10 ppm.

It is further preferred that the second virgin high-density polyethylene(C) has one or both of the following properties

-   -   a melt flow rate (ISO 1133, 21.6 kg, 190° C.) of from 3.0 to        15.0 g/10 min, preferably from 5.0 to 12.0 g/10 min; and/or    -   a comonomer content in the range from 1.0 to 5.0 wt.-%, more        preferably in the range from 1.5 to 3.0 wt.-%,

The second virgin high-density polyethylene (C) preferably includes aspolymeric component a copolymer of ethylene and one or more comonomerunits selected from alpha-olefins having from 3 to 8 carbon atoms. It ispreferred that the polymeric component is a copolymer of ethylene and1-butene or a copolymer of ethylene and 1-hexene, most preferably acopolymer of ethylene and 1-hexene.

The second virgin high-density polyethylene (C) is preferably present inthe composition of the present invention in an amount of from 2.0 to20.0 wt.-%, more preferably 3.0 to 18.0 wt.-%, still more preferably 4.0to 16.0 wt.-%, and most preferably from 5.0 to 15.0 wt.-%, based on theoverall weight of the composition.

Mixed-Plastic-Polyethylene Composition

The present invention seeks to provide a mixed-plastic-polyethylenecomposition comprising a mixed-plastic-polyethylene primary recyclingblend (A) with improved ESCR, impact strength and SH modulus compared tothe mixed-plastic-polyethylene primary recycling blend (A), to levelswhich are suitable for jacketing applications.

The mixed-plastic-polyethylene composition as described herein isespecially suitable for wire and cable applications, such as jacketingapplications.

In a first aspect the present invention relates to amixed-plastic-polyethylene composition comprising

-   -   a total amount of ethylene units (C2 units) of from 90.0 to 95        wt.-%, preferably 90.0 to 93.3 wt.-%, and    -   a total amount of continuous units having 3 carbon atoms        corresponding to polypropylene (continuous C3 units) of from 4.0        to 8.0 wt.-%, preferably 5.5 to 6.5 wt.-%,    -   a total amount of units having 4 carbon atoms (C4 units) of from        1.00 to 2.00 wt.-%, preferably 1.20 wt.-% to 1.40 wt.-%;        with the total amounts of C2 units, continuous C3 units and        units having 4 carbon atoms being based on the total weight        amount of monomer units in the composition and measured        according to quantitative ¹³C{¹H} NMR measurement,        and wherein the composition has    -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.1 to 0.9        g/10 min, and    -   a density of from 956 kg/m³ to 970 kg/m³.

In a preferable aspect the present invention relates to amixed-plastic-polyethylene composition comprising

-   -   a total amount of ethylene units (C2 units) of from 90.0 to 93.0        wt.-%, and    -   a total amount of continuous units having 3 carbon atoms        corresponding to polypropylene (continuous C3 units) of from 4.0        to 8.0 wt.-%, and    -   a total amount of units having 4 carbon atoms (C4 units) of from        1.20 wt.-% to 1.40 wt.-%;        with the total amounts of C2 units, continuous C3 units and        units having 4 carbon atoms being based on the total weight        amount of monomer units in the composition and measured        according to quantitative ¹³C{¹H} NMR measurement,        and wherein the composition has    -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.1 to 0.9        g/10 min, and    -   a density of from 958 kg/m³ to 968 kg/m³, preferably from 959 to        966 kg/m³.

In said aspect the mixed-plastic-polyethylene composition preferablycomprises carbon black in an amount of 1.0 to 3.0 wt.-% with respect tothe total of the mixed-plastic-polyethylene composition, more preferablyof 1.1 to 2.8 wt.-%, most preferably 1.2 to 2.6 wt.-%.

In said aspect the mixed-plastic-polyethylene composition is preferablyobtainable by blending and extruding

-   -   a) 10.0 to 70.0 wt.-% of a mixed-plastic-polyethylene primary        recycling blend (A) wherein 90.0 wt.-%, preferably 95.0 wt.-%,        more preferably 100.0 wt.-% of the mixed-plastic-polyethylene        primary blend (A) originates from post-consumer waste having a        limonene content of from 0.10 to 500 ppm; and wherein the        mixed-plastic-polyethylene primary blend (A) has        -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.1 to            1.5 g/10 min, preferably from 0.4 to 1.3 g/10 min,        -   a density of from 945 to 990 kg/m³,        -   optionally a shear thinning index SHI_(2.7/210) of 30 to 60,            preferably 35 to 50        -   optionally a polydispersity index from 1.2 to 2.5 s⁻¹, more            preferably 1.6 to 2.2 s⁻¹ as obtained from rheological            measurement,        -   and a content of units derived from ethylene of 70 to 95            wt.-% as determined by quantitative ¹³C{¹H}-NMR,    -   b) 25.0 to 88.0 wt.-% of a secondary component (B) being a        virgin high-density polyethylene (HDPE1) optionally blended with        carbon black, the secondary component (B) having        -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.1 to            1.2 g/10 min, preferably from 0.2 to 0.6 g/10 min;        -   a density of from 940 to 970 kg/m³, preferably from 955 to            970 kg/m³,        -   a shear thinning index SHI_(2.7/210) of 15 to 30        -   a polydispersity index from 1.6 to 2.2 s⁻¹ as obtained from            rheological measurement,        -   optionally a carbon black content of 1.5 to 3.0 wt.-% with            respect to the secondary component (B), and        -   preferably a limonene content below 2 ppm,    -   c) 2.0 to 20.0 wt.-% of a second virgin high-density        polyethylene (C) having        -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.05            to 0.7 g/10 min, more preferably from 0.05 to 1.0 g/10 min,            preferably from 0.10 to 0.5 g/10 min;        -   a density from 945 to 965 kg/m³,        -   a polydispersity index from 2.2 to 4.0 s⁻¹ as obtained from            rheological measurement; and        -   Preferably a limonene content below 0.10 ppm.

In a second aspect the present invention relates to amixed-plastic-polyethylene composition obtainable by blending andextruding

-   -   a) 10.0 to 70.0 wt.-% of a mixed-plastic-polyethylene primary        recycling blend (A) wherein 90.0 wt.-%, preferably 95.0 wt.-%,        more preferably 100.0 wt.-% of the mixed-plastic-polyethylene        primary blend (A) originates from post-consumer waste having a        limonene content of from 0.10 to 500 ppm; and wherein the        mixed-plastic-polyethylene primary blend (A) has        -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.1 to            1.5 g/10 min, preferably from 0.4 to 1.3 g/10 min,        -   a density of from 945 to 990 kg/m³,        -   optionally a shear thinning index SHI_(2.7/210) of 30 to 60,            preferably 35 to 50        -   optionally a polydispersity index from 1.2 to 2.5 s⁻¹,            preferably 1.6 to 2.2 s⁻¹ as obtained from rheological            measurement,        -   and a content of units derived from ethylene of 70 to 95            wt.-% as determined by quantitative ¹³C{¹H}-NMR,    -   b) 25.0 to 88.0 wt.-% of a secondary component (B) being a        virgin high-density polyethylene (HDPE1) optionally blended with        carbon black, the secondary component (B) having        -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.1 to            1.2 g/10 min, preferably from 0.2 to 0.6 g/10 min;        -   a density of from 940 to 970 kg/m³, preferably 955 to 970            kg/m³,        -   a shear thinning index SHI_(2.7/210) of 15 to 30        -   a polydispersity index from 1.6 to 2.2 s⁻¹ as obtained from            rheological measurement,        -   optionally a carbon black content of 1.5 to 3.0 wt.-% with            respect to the secondary component (B), and        -   preferably a limonene content below 2 ppm,    -   c) 2.0 to 20.0 wt.-% of a second virgin high-density        polyethylene (C) having        -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.05            to 1.0 g/10 min, preferably from 0.05 to 0.7 g/10 min, more            preferably from 0.10 to 0.5 g/10 min;        -   a density from 945 to 965 kg/m³,        -   a polydispersity index from 2.2 to 4.0 s⁻¹ as obtained from            rheological measurement; and        -   Preferably a limonene content below 0.10 ppm.

The mixed-plastic-polyethylene composition preferably comprises

-   -   a total amount of ethylene units (C2 units) of 91.0 to 94.0        wt.-%, more preferably from 92.0 to 93.3 wt.-%,    -   a total amount of continuous units having 3 carbon atoms        corresponding to polypropylene (continuous C3 units) of from 4.0        to 8.0 wt.-%, preferably from 5.5 wt.-% to 6.5 wt.-%, and    -   a total amount of units having 4 carbon atoms (C4 units) of 1.20        wt.-% to 1.40 wt.-%.

In a further preferred embodiment, the mixed-plastic-polyethylenecomposition comprises

-   -   a total amount of ethylene units (C2 units) of from 90.0 to 93.3        wt.-%,    -   a total amount of continuous units having 3 carbon atoms        corresponding to polypropylene (continuous C3 units) of from 5.5        to 6.5 wt.-%, and    -   a total amount of units having 4 carbon atoms (C4 units) of from        1.20 wt.-% to 1.40 wt.-%.

Further, the mixed-plastic-polyethylene composition preferably comprisesone or more in any combination of, more preferably all of:

-   -   a total amount of units having 3 carbon atoms as isolated peaks        in the NMR spectrum (isolated C3 units) of from 0.00 wt.-% to        0.20 wt.-%, more preferably from 0.00 wt.-% to 0.15 wt.-%, still        more preferably from 0.00 wt.-% to 0.12 wt.-%;    -   a total amount of units having 6 carbon atoms (C6 units) of from        0.00 wt.-% to 1.00 wt.-%, more preferably from 0.00 wt.-% to        0.75 wt.-%, still more preferably from 0.00 wt.-% to 0.50 wt.-%;    -   a total amount of units having 7 carbon atoms (C7 units) of from        0.00 wt.-% to 0.20 wt.-%, more preferably from 0.00 wt.-% to        0.15 wt.-%, still more preferably from 0.00 wt.-% to 0.10 wt.-%;        wherein the total amounts of isolated C3 units, C4 units, C6        units, C7 units are based on the total weight amount of monomer        units in the composition and are measured or calculated        according to quantitative ¹³C{¹H} NMR measurement.

Preferably, the total amounts of units, which can be attributed tocomonomers other than C4 (i.e. isolated C3 units, C6 units and C7units), in the mixed-plastic-polyethylene composition is from 0.00 wt.-%to 1.00 wt.-%, more preferably from 0.00 wt.-% to 0.60 wt.-%, still morepreferably from 0.00 wt.-% to 0.40 wt.-%, and is measured according toquantitative ¹³C{¹H}NMR measurement.

The mixed-plastic polyethylene composition according to the presentinvention has a

-   -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.1 to 0.9        g/10 min, preferably from 0.2 to 0.6 g/10 min;    -   a density of from 956 to 970 kg/m³, preferably 958 to 968 kg/m³,        more preferably from 959 to 966 kg/m³;

The composition can have further components apart from themixed-plastic-polyethylene primary recycling blend (A), the secondarycomponent (B) and the second virgin high-density polyethylene (C) suchas further polymeric components or additives in amounts of not more than15 wt.-%, based on the total weight of the composition.

Suitable additives are usual additives for utilization with polyolefins,such as stabilizers, (e.g. antioxidant agents), metal scavengers and/orUV stabilizers, antistatic agents, and utilization agents. The additivescan be present in the composition in an amount of 10 wt.-% or below,more preferably 9 wt.-% or below, more preferably 7 wt.-% or below.

It is, however, preferred that the composition consists of themixed-plastic-polyethylene primary recycling blend (A), the secondarycomponent (B) and the second virgin high-density polyethylene (C).

The mixed-plastic-polyethylene composition according to the presentinvention is preferably obtainable by blending and extruding

-   -   a) 10.0 to 70.0 wt.-% of a mixed-plastic-polyethylene primary        recycling blend (A)    -   b) 25.0 to 88.0 wt.-% of a secondary component (B) being a        virgin high-density polyethylene (HDPE1) optionally blended with        carbon black, and    -   c) 2.0 to 20.0 wt.-% of a second virgin high-density        polyethylene (C).

In a preferable embodiment, the composition is obtainable by blendingand extruding

-   -   a) 10.0 to 60.0 wt.-% of a mixed-plastic-polyethylene primary        recycling blend (A)    -   b) 30.0 to 85.0 wt.-% of a secondary component (B) being a        virgin high-density polyethylene (HDPE1) optionally blended with        carbon black, and    -   c) 3.0 to 18.0 wt.-% of a second virgin high-density        polyethylene (C).

In a further preferable embodiment, the composition is obtainable byblending and extruding

-   -   a) 15.0 to 50.0 wt.-% of a mixed-plastic-polyethylene primary        recycling blend (A)    -   b) 40.0 to 80.0 wt.-% of a secondary component (B) being a        virgin high-density polyethylene (HDPE1) optionally blended with        carbon black, and    -   c) 4.0 to 16.0 wt.-% of a second virgin high-density        polyethylene (C).

In a yet further preferable embodiment, the composition is obtainable byblending and extruding

-   -   a) 20.0 to 45.0 wt.-% of a mixed-plastic-polyethylene primary        recycling blend (A)    -   b) 50.0 to 75.0 wt.-% of a secondary component (B) being a        virgin high-density polyethylene (HDPE1) optionally blended with        carbon black, and    -   c) 5.0 to 15.0 wt.-% of a second virgin high-density        polyethylene (C).

The mixed-plastic-polyethylene primary recycling blend (A), thesecondary component (B) and the second virgin high-density polyethylene(C) are generally defined as described above or below.

The mixed plastic polyethylene composition preferably has an impactstrength at 23° C. (ISO 179-1 eA) of from 3.0 to 15.0 kJ/m², preferablyfrom 5.0 to 10.0 kJ/m².

Further, the mixed plastic polyethylene composition preferably has animpact strength at 0° C. (according to ISO 179-1 eA) of from 2.5 to 10.0kJ/m², more preferably from 4.1 to 8.0 kJ/m².

The mixed-plastic-polyethylene composition preferably has a strainhardening modulus (SH modulus) of from 15.0 to 25.0 MPa, more preferablyfrom 17.0 to 24.5 MPa and most preferably from 19.0 to 24.0 MPa.

It is preferred that that the mixed-plastic-polyethylene compositionpreferably has

-   -   a Shore D hardness, measured according to ISO 868 with a        measuring time of 1 s, Shore D 1 s, of from 55.0 to 70.0, more        preferably from 57.0 to 68.0 and most preferably from 60.0 to        65.0, and/or    -   a Shore D hardness, measured according to ISO 868 with a        measuring time of 3 s, Shore D 3 s, of from 55.0 to 70.0, more        preferably from 57.0 to 68.0 and most preferably from 60.0 to        65.0, and/or    -   a Shore D hardness, measured according to ISO 868 with a        measuring time of 15 s, Shore D 15 s, of from 55.0 to 70.0, more        preferably from 57.0 to 68.0 and most preferably from 60.0 to        65.0.

The mixed-plastic-polyethylene composition preferably has one or more,preferably all of the following rheological properties, in anycombination:

-   -   a shear thinning index SHI_(2.7/210) of from 35.0 to 50.0, more        preferably from 37 to 45, and/or    -   a complex viscosity at 0.05 rad/s, eta_(0.05), of from 28000 to        42000 Pa·s, more preferably from 31000 to 39000 Pa·s, and/or    -   a complex viscosity at 300 rad/s, eta₃₀₀, of from 650 to 850        Pa·s, more preferably from 700 to 800 Pa·s, and/or    -   a polydispersity index PI of from 2.2 to 3.0 s⁻¹, more        preferably from 2.4 to 2.8 s⁻¹.

Further, the mixed-plastic-polyethylene composition preferably has oneor more, preferably all of the following melt flow rate properties, inany combination:

-   -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.2 to 0.6        g/10 min, and/or    -   a melt flow rate (ISO 1133, 5 kg, 190° C.) of from 1.2 to 2.2        g/10 min, and/or    -   a melt flow rate (ISO 1133, 21 kg, 190° C.) of from 30.0 to 50.0        g/10 min.

Still further, the mixed-plastic-polyethylene composition preferably hasone or more, preferably all of the following tensile properties, in anycombination:

-   -   a tensile strain at break, measured according to ISO 527-2 on        compression moulded test specimens of type 5A, of from 500% to        780%, more preferably from 550% to 750%; and/or    -   a tensile stress at break, measured according to ISO 527-2 on        compression moulded test specimens of type 5A, of from 10 MPa to        30 MPa, more preferably from 15 MPa to 25 MPa.

Further, the mixed-plastic-polyethylene composition preferably has atear resistance of from 15.0 to 30.0 N/mm, more preferably of from 17.5to 27.5 N/mm and most preferably of from 20.0 to 25.0 N/mm. The tearresistance of the mixed-plastic-polyethylene composition is measured ona compression moulded plaque made from the composition having 1 mmthickness.

It is further preferred that the mixed-plastic-polyethylene compositionhas a pressure deformation of not more than 15%, more preferably notmore than 10%. The lower limit is usually at least 3%, preferably atleast 4%.

Still further, the mixed-plastic-polyethylene composition has a watercontent of preferably not more than 500 ppm more preferably not morethan 300 ppm. The lower limit is usually at least 10 ppm.

The mixed-plastic-polyethylene composition preferably also has an ESCR(Bell test failure time of at least 1000 hours, preferably at least 1500hours, most preferably at least 2000 hours.

Article

The present application is further directed to an article comprising themixed-plastic-polyethylene composition as described above.

In a preferred embodiment, the article is used in jacketing applicationsi.e. for a cable jacket. Preferably, the article is a cable comprisingat least one layer which comprises the mixed-plastic-polyethylenecomposition as described above.

Preferably, the cable comprising a layer such as a jacketing layer,which comprises the mixed-plastic-polyethylene composition as describedabove, has a cable shrinkage of not more than 2.0%, more preferably notmore than 1.5%. The lower limit is usually at least 0.3%, preferably atleast 0.5%.

All preferred aspects and embodiments as described above shall also holdfor the article.

Process

The present invention also relates to a process for preparing themixed-plastic-polyethylene composition as defined above or below. Theprocess according to the present invention results in an improvement inthe mechanical properties of the mixed-plastic-polyethylene primaryrecycling blend (A).

The process according to the present invention comprises the steps of:

-   -   a. providing a mixed-plastic-polyethylene primary recycling        blend (A) in an amount of 10.0 to 70.0 wt.-% based on the        overall weight of the composition,        -   wherein 90.0 wt.-%, preferably 95.0 wt.-%, more preferably            100.0 wt.-% of the mixed-plastic-polyethylene primary            blend (A) originates from post-consumer waste having a            limonene content of from 0.10 to 500 ppm and wherein the            mixed-plastic-polyethylene primary blend has        -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.1 to            1.5 g/10 min, preferably from 0.4 to 1.3 g/10 min,        -   a density of from 945 to 990 kg/m³,        -   optionally a shear thinning index SHI_(2.7/210) of 30 to 60,            preferably 35 to 50        -   optionally a polydispersity index from 1.2 to 2.5 s⁻¹, more            preferably 1.6 to 2.2 s⁻¹ as obtained from rheological            measurement,        -   and a content of units derived from ethylene of 70.0 to 95.0            wt.-% as determined by quantitative ¹³C{1H}-NMR,    -   b. providing a secondary component (B) being a virgin        high-density polyethylene (HDPE1) optionally blended with carbon        black, in an amount of 25.0 to 88.0 wt.-% based on the overall        weight of the composition, the secondary component (B) having        -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.1 to            1.2 g/10 min, preferably from 0.2 to 0.6 g/10 min,        -   a density of from 940 to 970 kg/m³, preferably 955 to 970            kg/m³,        -   a shear thinning index SHI_(2.7/210) of 15 to 30,        -   a polydispersity index from 1.6 to 2.2 s⁻¹ as obtained from            rheological measurement,        -   optionally a carbon black content of 1.5 to 3.0 wt.-% with            respect to the secondary component (B); and        -   preferably, a limonene content below 0.10 ppm.    -   c. Providing a second virgin high-density polyethylene (C) in an        amount of 2.0 to 20.0 wt.-%, based on the overall weight of the        composition, the second virgin high-density polyethylene having        -   a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.05            to 1.0 g/10 min, preferably from 0.05 to 0.7 g/10 min, more            preferably from 0.10 to 0.5 g/10 min;        -   a density from 945 to 965 kg/m³,        -   a polydispersity index from 2.2 to 4.0 s⁻¹ as obtained from            rheological measurement; and        -   Preferably a limonene content below 0.10 ppm    -   d. melting and mixing the blend of mixed-plastic-polyethylene        primary blend (A), the secondary component (B) and the second        virgin high-density polyethylene (C) in an extruder, optionally        a twin screw extruder, and    -   e. optionally pelletizing the obtained        mixed-plastic-polyethylene composition.

All preferred aspects, definitions and embodiments as described aboveshall also hold for the process.

Experimental Part

1. Test Methods

a) Melt Flow Rate

Melt flow rates were measured with a load of 2.16 kg (MFR₂), 5.0 kg(MFR₅) or 21.6 kg (MFR₂₁) at 190° C. as indicated. The melt flow rate isthat quantity of polymer in grams which the test apparatus standardizedto ISO 1133 extrudes within 10 minutes at a temperature of or 190° C.under a load of 2.16 kg, 5.0 kg or 21.6 kg.

b) Density

Density is measured according to ISO 1183-187. Sample preparation isdone by compression moulding in accordance with ISO 17855-2.

c) Comonomer Content

Quantification of C4 in polyethylene by NMR spectroscopy (used forcarrier polylethylene of the carbon black masterbatch) Quantitativenuclear-magnetic resonance (NMR) spectroscopy was used to quantify thecomonomer content of the polymer.

Quantitative ¹³C{¹H} NMR spectra recorded in the molten-state using aBruker Avance III 500 NMR spectrometer operating at 500.13 and 125.76MHz for ¹H and ¹³C respectively. All spectra were recorded using a ¹³Coptimised 7 mm magic-angle spinning (MAS) probehead at 150° C. usingnitrogen gas for all pneumatics. Approximately 200 mg of material waspacked into a 7 mm outer diameter zirconia MAS rotor and spun at 4 kHz.This setup was chosen primarily for the high sensitivity needed forrapid identification and accurate quantification {klimke06, parkinson07,castignolles09}. Standard single-pulse excitation was employed utilisingthe transient NOE at short recycle delays of 3 s {pollard04, klimke06}and the RS-HEPT decoupling scheme {fillip05, griffin07}. A total of 1024(1 k) transients were acquired per spectrum. This setup was chosen dueits high sensitivity towards low comonomer contents.

Quantitative ¹¹C{¹H} NMR spectra were processed, integrated andquantitative properties determined using custom spectral analysisautomation programs. All chemical shifts are internally referenced tothe bulk methylene signal (δ+) at 30.00 ppm {randall89}.

Characteristic signals corresponding to the incorporation of 1-butenewere observed (randall89) and all contents calculated with respect toall other monomers present in the polymer.

Characteristic signals resulting from isolated 1-butene incorporationi.e. EEBEE comonomer sequences, were observed. Isolated 1-buteneincorporation was quantified using the integral of the signal at 39.9ppm assigned to the _(*)B2 sites, accounting for the number of reportingsites per comonomer:

B=I _(*B2)

With no other signals indicative of other comonomer sequences, i.e.consecutive comonomer incorporation, observed the total 1-butenecomonomer content was calculated based solely on the amount of isolated1-butene sequences:

B _(total) =B

The relative content of ethylene was quantified using the integral ofthe bulk methylene (□+) signals at 30.00 ppm:

E=(1/2)*I _(□+)

The total ethylene comonomer content was calculated based the bulkmethylene signals and accounting for ethylene units present in otherobserved comonomer sequences:

E _(total) =E+(5/2)*B

The total mole fraction of 1-butene in the polymer was then calculatedas:

fB=B _(total)/(E _(total) +B _(total))

The total comonomer incorporation of 1-butene in mole percent wascalculated from the mole fraction in the usual manner:

B[mol %]=100*fB

The total comonomer incorporation of 1-butene in weight percent wascalculated from the mole fraction in the standard manner:

B[wt %]=100*fB*56.11/((fB*56.11)+((1−fB)*28.05))

-   klimke06-   Klimke, K., Parkinson, M., Piel, C., Kaminsky, W., Spiess, H. W.,    Wilhelm, M., Macromol. Chem. Phys. 2006; 207:382.-   parkinson07-   Parkinson, M., Klimke, K., Spiess, H. W., Wilhelm, M., Macromol.    Chem. Phys. 2007; 208:2128.-   pollard04-   Pollard, M., Klimke, K., Graf, R., Spiess, H. W., Wilhelm, M.,    Sperber, O., Piel, C., Kaminsky, W., Macromolecules 2004; 37:813.-   filip05-   Filip, X., Tripon, C., Filip, C., J. Mag. Resn. 2005, 176, 239-   griffin07-   Griffin, J. M., Tripon, C., Samoson, A., Filip, C., and Brown, S.    P., Mag. Res. in Chem. 2007 45, S1, S198-   castignolles09-   Castignolles, P., Graf, R., Parkinson, M., Wilhelm, M., Gaborieau,    M., Polymer 50 (2009) 2373-   randall89-   J. Randall, Macromol. Sci., Rev. Macromol. Chem. Phys. 1989, C29,    201.

Quantification of C2, iPP (Continuous C3), LDPE and Polyethylene ShortChain Branches

Quantitative ¹³C{¹H} NMR spectra were recorded in the solution-stateusing a Bruker AvanceIII 400 MHz NMR spectrometer operating at 400.15and 100.62 MHz for ¹H and ¹³C respectively. All spectra were recordedusing a ¹³C optimised 10 mm extended temperature probehead at 125° C.using nitrogen gas for all pneumatics. Approximately 200 mg of materialwas dissolved in 3 ml of 1,2-tetrachloroethane-d₂ (TCE-d₂) along withchromium-(III)-acetylacetonate (Cr(acac)₃) resulting in a 65 mM solutionof relaxation agent in solvent {singh09}. To ensure a homogenoussolution, after initial sample preparation in a heat block, the NMR tubewas further heated in a rotatory oven for at least 1 hour. Uponinsertion into the magnet the tube was spun at 10 Hz. This setup waschosen primarily for the high resolution and quantitatively needed foraccurate ethylene content quantification. Standard single-pulseexcitation was employed without NOE, using an optimised tip angle, 1 srecycle delay and a bi-level WALTZ16 decoupling scheme {zhou07,busico07}. A total of 6144 (6 k) transients were acquired per spectra.

Quantitative ¹³C{¹H} NMR spectra were processed, integrated and relevantquantitative properties determined from the integrals using proprietarycomputer programs. All chemical shifts were indirectly referenced to thecentral methylene group of the ethylene block (EEE) at 30.00 ppm usingthe chemical shift of the solvent. Characteristic signals correspondingto polyethylene with different short chain branches (1, B2, B4, B5,E6plus) and polypropylene were observed {randall89, brandolini00}.

Characteristic signals corresponding to the presence of polyethylenecontaining isolated 1 branches (starB1 33.3 ppm), isolated B2 branches(starB2 39.8 ppm), isolated B4 branches (twoB4 23.4 ppm), isolated B5branches (threeB5 32.8 ppm), all branches longer than 4 carbons(starB4plus 38.3 ppm) and the third carbon from a saturated aliphaticchain end (3 s 32.2 ppm) were observed. The intensity of the combinedethylene backbone methine carbons (ddg) containing the polyethylenebackbone carbons (dd 30.0 ppm), γ-carbons (g 29.6 ppm) the 4 s and thethreeB4 carbon (to be compensated for later on) is taken between 30.9ppm and 29.3 ppm excluding the Tββ from polypropylene. The amount of C2related carbons was quantified using all mentioned signals according tothe following equation:

fC_(C2total)=(Iddg−ItwoB4)+(IstarB1*6)+(IstarB2*7)+(ItwoB4*9)+I(threeB5*10)+((IstarB4plus−ItwoB4−IthreeB5)*7)+(13s*3)

Characteristic signals corresponding to the presence of polypropylene(iPP, continuous C3)) were observed at 46.7 ppm, 29.0 ppm and 22.0 ppm.The amount of PP related carbons was quantified using the integral ofSαα at 46.6 ppm:

fC _(PP) =Isαα*3

The weight percent of the C2 fraction and the polypropylene can bequantified according following equations:

wt_(C2fraction) =fC _(C2total)*100/(fC _(C2total) +fC _(PP))

wt_(PP) =fC _(PP)*100/(fC _(C2total) +fC _(PP))

Characteristic signals corresponding to various short chain brancheswere observed and their weight percentages quantified as the relatedbranch would be an alpha-olefin, starting by quantifying the weightfraction of each:

fwtC2=fC _(C2total)−((IstarB1*3)−(IstarB2*4)−(ItwoB4*6)−(IthreeB5*7)

fwtC3(isolated C3)=IstarB1*3

fwtC4=IstarB2*4

fwtC6=ItwoB4*6

fwtC7=IthreeB5*7

Normalisation of all weight fractions leads to the amount of weightpercent for all related branches:

fsum_(wt.-% total) =fwtC2+fwtC3+fwtC4+fwtC6+fwtC7+fC _(PP)

wtC2total=fwtC2*100/fsum_(wt.-% total)

wtC3total=fwtC3*100/fsum_(wt.-% total)

wtC4total=fwtC4*100/fsum_(wt.-% total)

wtC6total=fwtC6*100/fsum_(wt.-% total)

wtC7total=fwtC7*100/fsum_(wt.-% total)

The content of LDPE can be estimated assuming the B5 branch, which onlyarises from ethylene being polymerised under high pressure process,being almost constant in LDPE.

We found the average amount of B5 if quantified as C7 at 1.46 wt.-%.With this assumption it is possible to estimate the LDPE content withincertain ranges (approximately between 20 wt.-% and 80 wt.-%), which aredepending on the SNR ratio of the threeB5 signal:

wt.-% LDPE=wtC7total*100/1.46

REFERENCES

-   zhou07 Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R.,    Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225-   busico07 Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R.,    Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128-   singh09 Singh, G., Kothari, A., Gupta, V., Polymer Testing 28 5    (2009), 475-   randall89 J. Randall, Macromol. Sci., Rev. Macromol. Chem. Phys.    1989, C29, 201.-   brandolini00 A. J. Brandolini, D. D. Hills, NMR Spectra of Polymers    and Polymer Additives, Marcel Dekker Inc., 2000

d) Impact Strength

The impact strength is determined as Charpy Notched Impact Strengthaccording to ISO 179-1 eA at +23° C. and at 0° C. on compression mouldedspecimens of 80×10×4 mm prepared according to ISO 17855-2.

e) Tensile Testing of 5A Specimen

For tensile testing, dog bone specimens of 5A are prepared according toISO 527-2/5A by die cutting from compression moulded plaques of 2 mm′thickness. If ageing is needed, the 5A specimens are kept at 110° C. ina cell oven for 14 days (336 hours). All specimens are conditioned forat least 16 hours at 23° C. and 50% relative humidity before testing.

Tensile properties are measured according to ISO 527-1/2 at 23° C. and50% relative humidity with Alwetron R24, 1 kN load cell. Tensile testingspeed is 50 mm/min, grip distance is 50 mm and gauge length is 20 mm.

f) Rheological Measurements

Dynamic Shear Measurements (frequency sweep measurements) Thecharacterisation of melt of polymer composition or polymer as givenabove or below in the context by dynamic shear measurements complieswith ISO standards 6721-1 and 6721-10. The measurements were performedon an Anton Paar MCR501 stress controlled rotational rheometer, equippedwith a 25 mm parallel plate geometry. Measurements were undertaken oncompression moulded plates, using nitrogen atmosphere and setting astrain within the linear viscoelastic regime. The oscillatory sheartests were done at 190° C. applying a frequency range between 0.01 and600 rad/s and setting a gap of 1.3 mm.

In a dynamic shear experiment the probe is subjected to a homogeneousdeformation at a sinusoidal varying shear strain or shear stress (strainand stress controlled mode, respectively). On a controlled strainexperiment, the probe is subjected to a sinusoidal strain that can beexpressed by

γ(t)=γ₀ sin(ωt)  (1)

If the applied strain is within the linear viscoelastic regime, theresulting sinusoidal stress response can be given by

σ(t)=σ₀ sin(ωt+δ)  (2)

whereσ₀ and γ₀ are the stress and strain amplitudes, respectivelyω is the angular frequencyδ is the phase shift (loss angle between applied strain and stressresponse)t is the time

Dynamic test results are typically expressed by means of severaldifferent rheological functions, namely the shear storage modulus G′,the shear loss modulus, G″, the complex shear modulus, G*, the complexshear viscosity, η*, the dynamic shear viscosity, η′, the out-of-phasecomponent of the complex shear viscosity r″ and the loss tangent, tan δwhich can be expressed as follows:

$\begin{matrix}{G^{\prime} = {\frac{\sigma_{0}}{\gamma_{0}}\cos{\delta\lbrack{Pa}\rbrack}}} & (3)\end{matrix}$ $\begin{matrix}{G^{''} = {\frac{\sigma_{0}}{\gamma_{0}}\sin{\delta\lbrack{Pa}\rbrack}}} & (4)\end{matrix}$ $\begin{matrix}{G^{*} = {G^{\prime} + {{iG}^{''}\lbrack{Pa}\rbrack}}} & (5)\end{matrix}$ $\begin{matrix}{\eta^{*} = {\eta^{\prime} - {i{\eta^{''}\left\lbrack {{Pa}.s} \right\rbrack}}}} & (6)\end{matrix}$ $\begin{matrix}{\eta^{\prime} = {\frac{G^{''}}{\omega}\left\lbrack {{Pa}.s} \right\rbrack}} & (7)\end{matrix}$ $\begin{matrix}{\eta^{''} = {\frac{G^{\prime}}{\omega}\left\lbrack {{Pa}.s} \right\rbrack}} & (8)\end{matrix}$

The determination of so-called Shear Thinning Index, which correlateswith MWD and is independent of Mw, is done as described in equation 9.

$\begin{matrix}{{SHI}_{({x/y})} = \frac{{Eta}^{\star}{for}\left( {G^{\star} = {x{kPa}}} \right)}{{Eta}^{\star}{for}\left( {G^{\star} = {y{kPa}}} \right)}} & (9)\end{matrix}$

For example, the SHI_(2.7/210) is defined by the value of the complexviscosity, in Pa s, determined for a value of G* equal to 2.7 kPa,divided by the value of the complex viscosity, in Pa s, determined for avalue of G* equal to 210 kPa.

The values of storage modulus (G′), loss modulus (G″), complex modulus(G*) and complex viscosity (η*) were obtained as a function of frequency(ω).

Thereby, e.g. η*_(300 rad/s) (eta*_(300 rad/s)) is used as abbreviationfor the complex viscosity at the frequency of 300 rad/s andη*_(0.05 rad/s) (eta*_(0.05 rad/s)) is used as abbreviation for thecomplex viscosity at the frequency of 0.05 rad/s.

The loss tangent tan (delta) is defined as the ratio of the loss modulus(G″) and the storage modulus (G′) at a given frequency. Thereby, e.g.tan_(0.05) is used as abbreviation for the ratio of the loss modulus(G″) and the storage modulus (G′) at 0.05 rad/s and tan₃₀₀ is used asabbreviation for the ratio of the loss modulus (G″) and the storagemodulus (G′) at 300 rad/s.

The elasticity balance tan_(0.05)/tan₃₀₀ is defined as the ratio of theloss tangent tan_(0.05) and the loss tangent tan₃₀₀.

Besides the above mentioned rheological functions one can also determineother rheological parameters such as the so-called elasticity indexEI(x). The elasticity index EI(x) is the value of the storage modulus(G) determined for a value of the loss modulus (G″) of x kPa and can bedescribed by equation 10.

EI(x)=G′ for (G″=x kPa)[Pa]  (10)

For example, the E/(5 kPa) is the defined by the value of the storagemodulus (G′), determined for a value of G″ equal to 5 kPa.

The polydispersity index, PI, is defined by equation 11.

$\begin{matrix}{{{PI} = \frac{{- 1}0^{5}}{G^{\prime}\left( \omega_{COP} \right)}},{\omega_{COP} = {\omega{for}\left( {G^{\prime} = G^{''}} \right)}}} & (11)\end{matrix}$

where ω_(COP) is the cross-over angular frequency, determined as theangular frequency for which the storage modulus, G′, equals the lossmodulus, G″.

The values are determined by means of a single point interpolationprocedure, as defined by Rheoplus software. In situations for which agiven G* value is not experimentally reached, the value is determined bymeans of an extrapolation, using the same procedure as before.

In both cases (interpolation or extrapolation), the option from Rheoplus“Interpolate y-values to x-values from parameter” and the “logarithmicinterpolation type” were applied.

REFERENCES

-   [1] Rheological characterization of polyethylene fractions”    Heino, E. L., Lehtinen, A., Tanner J., Seppälä, J., Neste Oy,    Porvoo, Finland, Theor. Appl. Rheol., Proc. Int. Congr. Rheol, 11th    (1992), 1, 360-362-   [2] The influence of molecular structure on some rheological    properties of polyethylene”, Heino, E. L., Borealis Polymers Oy,    Porvoo, Finland, Annual Transactions of the Nordic Rheology Society,    1995).-   [3] Definition of terms relating to the non-ultimate mechanical    properties of polymers, Pure & Appl. Chem., Vol. 70, No. 3, pp.    701-754, 1998.

g) ESCR (Bell Test, h)

By the term ESCR (environmental stress cracking resistance) is meant theresistance of the polymer to crack formation under the action ofmechanical stress and a reagent in the form of a surfactant. The ESCR isdetermined in accordance with IEC 60811-406, method B. The reagentemployed is 10 weight % Igepal CO 630 in water. The materials wereprepared according to instructions for HDPE as follows: The materialswere pressed at 165° C. to a thickness of 1.75-2.00 mm. The notch was0.30-0.40 mm deep.

h) Shore D Hardness

Two different Shore D hardness measurements were conducted:

Firstly, Shore D hardness is determined according to ISO 868 on mouldedspecimen with a thickness of 4 mm. The shore hardness is determinedafter 1 sec, 3 sec or 15 sec after the pressure foot is in firm contactwith the test specimen. The sample is compression moulded according toISO 17855-2 and milled into specimens of 80×10×4 mm.

i) Strain Hardening (SH) Modulus

The strain hardening test is a modified tensile test performed at 80° C.on a specially prepared thin sample. The Strain Hardening Modulus (MPa),<Gp>, is calculated from True Strain-True Stress curves; by using theslope of the curve in the region of True Strain, λ, is between 8 and 12.

The true strain, λ, is calculated from the length, l (mm), and the gaugelength, l0 (mm), as shown by Equation 1.

$\begin{matrix}{\lambda = {\frac{l}{l_{0}} = {1 + \frac{\Delta l}{l_{0}}}}} & (1)\end{matrix}$

where Δl is the increase in the specimen length between the gauge marks,(mm). The true stress, σtrue (MPa), is calculated according to formula2, assuming conservation of volume between the gauge marks:

σ_(true)=σ_(n)λ  (2)

where σ_(n) is the engineering stress.

The Neo-Hookean constitutive model (Equation 3) is used to fit the truestrain-true stress data from which <Gp> (MPa) for 8<λ<12 is calculated.

$\begin{matrix}{\sigma_{true} = {{\frac{< {Gp} >}{20}\left( {\lambda^{2} - \frac{1}{\lambda}} \right)} + C}} & (3)\end{matrix}$

where C is a mathematical parameter of the constitutive model describingthe yield stress extrapolated to λ=0.

Initially five specimens are measured. If the variation coefficient of<Gp> is greater than 2.5%, then two extra specimens are measured. Incase straining of the test bar takes place in the clamps the test resultis discarded.

The PE granules of materials were compression molded in sheets of 0.30mm thickness according to the press parameters as provided in ISO17855-2.

After compression molding of the sheets, the sheets were annealed toremove any orientation or thermal history and maintain isotropic sheets.Annealing of the sheets was performed for 1 h in an oven at atemperature of (120±2) ° C. followed by slowly cooling down to roomtemperature by switching off the temperature chamber. During thisoperation free movement of the sheets was allowed.

Next, the test pieces were punched from the pressed sheets. The specimengeometry of the modified ISO 37:1994 Type 3 (FIG. 3) was used.

The sample has a large clamping area to prevent grip slip, dimensionsgiven in Table 1.

TABLE 1 Dimensions of Modified ISO 37: 1994 Type 3 Dimension Size (mm) Lstart length between clamps 30.0 +/− 0.5  l0 Gauge length 12.5 +/− 0.1 l1 Prismatic length 16.0 +/− 1.0  l3 Total length 70 R1 Radius 10.0 +/−0.03 R2 Radius 8.06 +/− 0.03 b1 Prismatic width  4.0 +/− 0.01 b2 Clampwidth 20.0 +/− 1.0  h Thickness 0.30 + 0.05/0.30 − 0.03

The punching procedure is carried out in such a way that no deformation,crazes or other irregularities are present in the test pieces.

The thickness of the samples was measured at three points of theparallel area of the specimen; the lowest measured value of thethickness of these measurements was used for data treatment.

-   1. The following procedure is performed on a universal tensile    testing machine having controlled temperature chamber and    non-contact extensometer:-   2. Condition the test specimens for at least 30 min in the    temperature chamber at a temperature of (80±1) ° C. prior to    starting the test.-   3. Clamp the test piece on the upper side.-   4. Close the temperature chamber.-   5. Close the lower clamp after reaching the temperature of (80±1) °    C.-   6. Equilibrate the sample for 1 min between the clamps, before the    load is applied and measurement starts.-   7. Add a pre-load of 0.5 N at a speed of 5 mm/min.-   8. Extend the test specimen along its major axis at a constant    traverse speed (20 mm/min) until the sample breaks.    -   During the test, the load sustained by the specimen is measured        with a load cell of 200 N. The elongation is measured with a        non-contact extensometer.

j) Water Content

The water content was determined as described in ISO15512:2019 MethodA—Extraction with anhydrous methanol. There the test portion isextracted with anhydrous methanol and the extracted water is determinedby a coulometric Karl Fischer Titrator.

k) Cable Extrusion

The cable extrusion is done on a Nokia-Maillefer cable line. Theextruder has five temperature zones with temperatures of170/175/180/190/190° C. and the extruder head has three zones withtemperatures of 210/210/210° C. The extruder screw is a barrier screw ofthe design Elise. The die is a semi-tube on type with 5.9 mm diameterand the outer diameter of the cable is 5 mm. The compound is extruded ona 3 mm in diameter, solid aluminum conductor to investigate theextrusion properties. Line speed is 75 m/min. The pressure at the screenand the current consumption of the extruder is recorded for eachmaterial.

l) Pressure Deformation

Pressure test is conducted according to EN 60811-508. An extruded cablesample is placed in an air oven at a 115° C. and subjected to a constantload applied by means of a special indentation device (with arectangular indentation 0.7 mm wide knife) for 6 hours. The percentageof indentation is measured afterwards using a digital gauge.

m) Cable Shrinkage

The shrinkage of the composition is determined with the cable samplesobtained from the cable extrusion. The cables are conditioned in theconstant room at least 24 hours before the cutting of the samples. Theconditions in the constant room are 23±2° C. and 50±5% humidity. Samplesare cut to 400 mm at least 2 m away from the cable ends. They arefurther conditioned in the constant room for 24 hours after which theyare place in an oven on a talcum bed at 100° C. for 24 hours. Afterremoval of the sample from the oven they are allowed to cool down toroom temperature and then measured. The shrinkage is calculatedaccording to formula below:

[(L _(Before) −L _(After))/L _(Before)]×100%, wherein L is length.

n) Tear Resistance

Tear resistance is measured on compression moulded plaques of 1 mmthickness according to BS 6469 section 99.1. A test piece with a cut isused to measure the tear force by means of a tensile testing machine.The tear resistance is calculated by dividing the maximum force neededto tear the specimen by its thickness.

o) Amount of Limonene

This method allows nature of a raw mixed-plastic-polyethylene primaryrecycling blend to be determined.

Limonene quantification was carried out using solid phasemicroextraction (HS-SPME-GC-MS) by standard addition.

20 mg cryomilled samples were weighed into 20 mL headspace vials andafter the addition of limonene in different concentrations and aglass-coated magnetic stir bar, the vial was closed with a magnetic caplined with silicone/PTFE. Micro capillaries (10 pL) were used to adddiluted limonene standards of known concentrations to the sample.Limonene was added to the samples to obtain concentration levels of 1ppm, 2 ppm, 3 ppm and 4 ppm limonene. For quantification, ion-93acquired in SIM mode was used. Enrichment of the volatile fraction wascarried out by headspace solid phase microextraction with a 2 cm stableflex 50/30 pm DVB/Carboxen/PDMS fibre at 60° C. for 20 minutes.Desorption was carried out directly in the heated injection port of aGCMS system at 270° C.

GCMS Parameters:

Column: 30 m HP 5 MS 0.25*0.25

Injector: Splitless with 0.75 mm SPME Liner, 270° C.

Temperature program: −10° C. (1 min)

MS: Single quadrupole, direct interface, 280° C. interface temperature

Acquisition: SIM scan mode

Scan parameter: 20-300 amu

SIM Parameter: m/Z 93, 100 ms dwell time

2. Materials

PE1 is HE6062, a black bimodal high density polyethylene jacketingcompound for energy and communication cables (available from BorealisAG). (see Table 2 for properties) PE2 is HE6063, a natural bimodal highdensity polyethylene jacketing compound for energy and communicationcables (available from Borealis AG). (see Table 2 for properties)

PE3 is BorSafe™ HE3490-LS-H, a black bimodal high density polyethylene(available from Borealis AG). (see Table 2 for properties)

PE4 is BorSafe™ HE3493-LS-H, a natural bimodal high density polyethylene(available from Borealis AG). (see Table 2 for properties)

Purpolen PE is a mixed-plastic-polyethylene primary recycling blendavailable from MTM plastics. Various samples of Purpolen PE, differingas to density and also rheology, were used in the present study, withthe measured properties of these samples given in Table 1.

TABLE 1 Purpolen PE properties Purpolen PE1 Purpolen PE2 C2 content(wt.-%)   87.42   74.22 Isolated C3 content   0.17   0.32 (wt.-%) C4content (wt.-%)   0.39   0.21 C6 content (wt.-%)   0.48   0.18 C7content (wt.-%)   0*   0* Continuous C3   11.53   25.07 content (wt.-%)Limonene content   6 n.m. (ppm) MFR₂ (g/10 min)   0.80   0.91 MFR₅ (g/10min)   3.55   4.23 MFR₂₁ (g/10 min) n.m.   89.7 Density (kg/m³)  983 951 W_(COP)   67.5   46.9 PI (s⁻¹)   1.7   2.0 SHI_(2.7/210)   40.3  45.7 eta_(0.05) (Pa · s) 27600 30100 eta₃₀₀ (Pa · s)  560  560 XHU(wt.-%)   0.27   0.26 Water content (%)  262 n.m. *0 means lower thanthe limit of quantification n.m.; not measured.

TABLE 2 Virgin HDPE properties PE1 PE2 PE3 PE4 C2 content (wt.-%)  97.72   97.47   98.14 n.m. Isolated C3 content   0*   0*    0* n.m.(wt.-%) C4 content (wt.-%)   2.28   2.53    0* n.m. C6 content (wt.-%)  0*   0*    1.86 n.m. C7 content (wt.-%)   0*   0*    0* n.m.Continuous C3   0*   0*    0* n.m. content (wt.-%) CB content (wt.-%)  2.44   0*    2.17 n.m. MFR₂ (g/10 min)   0.5   0.55 n.m. n.m. MFR₅(g/10 min)   1.85   2    0.25    0.21 MFR₂₁ (g/10 min)   38.66   40   9.7    6.64 Density (kg/m³)  959.9  945.8   960   952 W_(COP)   19.52  21.73    0.75    1.06 PI (s⁻¹)   1.87   1.9    3.62    2.68 SH modulus(MPa)   25.38   27.43   71   81 SHI_(2.7/210)   21.95   22.07 n.m. n.m.eta_(0.05) (Pa · s) 26074 21897 167000 175000 eta₃₀₀ (Pa · s)  815  760 1070  1280 *0 means lower than the limit of quantification n.m.: notmeasured

3. Experiments

Compositions were prepared via melt blending on a co-rotating twin screwextruder (ZSK) according to the recipes given in Table 4. The polymermelt mixture was discharged and pelletized. Table 3 further shows thecontent of these compositions, as measured by quantitative ¹³C{¹H} NMRmeasurements. The mechanical properties of the compositions are given inTable 4.

TABLE 3 Composition of Comparative and Inventive Examples CE1 IE1 IE2CE2 IE3 PE1 (wt.-%) 50  50  50  — — PE2 (wt.-%) — — — 70  60  PE3(wt.-%) — 5 10  — — PE4 (wt.-%) — — — — 15  Purpolen PE1 (wt.-%) 50  45 40  — — Purpolen PE2 (wt.-%) — — — 25  25  CB content (wt.-%)   1.3  1.5   1.6    2.21*   2.3* C2 content (wt.-%)  91.8  92.0  93.2  92.3 92.2 Isolated C3 content  0**  0**  0**  0**   0.10 (wt.-%) C4 content(wt.-%)   1.3   1.3   1.2   1.9   1.3 C6 content (wt.-%)  0**  0**  0** 0**   0.4 C7 content (wt.-%)  0**  0**  0**  0**  0** Continuous C3  6.9   6.7   5.6   5.8   6.0 content (wt.-%) *The carbon black in CE2and IE3 results from the introduction of 6.3 wt.-% of a 40% carbon blackmasterbatch in the melt blending step. The polyethylene as used as thecarrier polyethylene has an MFR₂ of 12.1 g/10 min, an MFR₅ of 34.8 g/10min, an MFR₂₁ of 312 g/10 min, a density of 963, eta_(0.05) of 870 Pa ·s, eta₃₀₀ of 291 Pa · s and a C4 content of < 0.4 wt.-%. **0 means lowerthan the limit of quantification

TABLE 4 Mechanical properties of Comparative and Inventive Examples CE1IE1 IE2 CE2 IE3 MFR₂ (g/10 min) 0.51 0.47 0.38 0.60 0.39 MFR₅ (g/10 min)2.34 1.94 1.70 2.55 1.71 MFR₂₁ (g/10 min) 48.2 47.1 41.5 49.6 37.5Density (kg/m³) 966 966 965 959 959 Impact strength, 23° C., 4.7 5.4 6.66.0 7.2 (kJ/m²) Impact strength, 0° C., 4.1 4.3 4.2 3.9 4.3 (kJ/m²)W_(COP) 22.6 16.4 12.5 25.0 11.2 PI (s⁻¹) 2.3 2.4 2.6 2.0 2.6SHI_(2.7/210) 35.7 38.1 41.8 28.6 41.7 eta_(0.05) (Pa · s) 28300 3290036900 24000 38100 eta₃₀₀ (Pa · s) 670 710 730 690 740 Bell ESCR (h) 8401632 >4000 >4000 >4000 Cable shrinkage (%) 1.08 1.12 1.22 0.62 0.73Pressure deformation (%) 5 6 7 n.m. n.m. SH modulus (MPa) 16.2 17.3 19.319.9 23.8 Shore D 15 s (ISO 868) 61.1 61.2 61.4 n.m. n.m. Shore D 3 s(ISO 868) 63.4 63.3 63.3 n.m. n.m. Shore D 1 s (ISO 868) 64.5 64.7 64.9n.m. n.m. Tensile strain at break, 400 640 580 470 650 5A specimen (%)Tensile stress at break, 14.2 15.1 15.5 15.0 16.8 5A specimen (MPa) Tearresistance (N/mm) 22.8 22.8 23.1 n.m. n.m. Water content (%) 179 299 28979 13 n.m. = not measured

As can be seen from Table 4, the addition of either PE4 or PE5 to blendsof PE1/PE2 with Purpolen PE has the effect of increasing the Charpynotched impact strength, the tensile strain and stress at break, andparticularly ECSR (evaluated by Bell test and/or strain hardeningmodulus). As can be seen from CE1, when relatively large amounts ofrecycled material are used, this can result in poor Charpy notchedimpact strength, ECSR performance and SH modulus being too low.Inclusion of the second virgin high-density polyethylene (C) allowsaccess to black compositions that satisfy the requirements for cablingapplications and additionally have a higher recycled content than wouldbe possible without the addition of said second virgin high-densitypolyethylene (C), a key result, given the ever-stricter requirementsregarding the content of recycled material in consumer goods.

It further can be seen that the simultaneous presence of an amount ofcontinuous C3 units from 5.5 to 6.5 wt.-% and C4 units from 1.20 to 1.40wt.-% such as in example IE2 and IE3 results in surprisingly high andunexpected Bell ESCR as well as better impact strength (23° C.) withcomparable impact strength (0°).

1. A mixed-plastic-polyethylene composition comprising amixed-plastic-polyethylene primary recycling blend (A), themixed-plastic-polyethylene composition having a melt flow rate (ISO1133, 2.16 kg, 190° C.) of from 0.1 to 0.9 g/10 min; a density of from956 kg/m³ to 970 kg/m³; the mixed-plastic-polyethylene compositioncomprising a total amount of ethylene units (C2 units) of from 90.0 to95 wt.-%, and a total amount of continuous units having 3 carbon atomscorresponding to polypropylene (continuous C3 units) of from 4.0 to 8.0wt.-%, a total amount of units having 4 carbon atoms (C4 units) of from1.00 to 2.00 wt.-%; with the total amounts of C2 units, continuous C3units and units having 4 carbon atoms being based on the total weightamount of monomer units in the composition and measured according toquantitative ¹³C{¹H} NMR measurement, wherein themixed-plastic-polyethylene composition is obtained by blending andextruding a. 10.0 to 70.0 wt.-% of a mixed-plastic-polyethylene primaryrecycling blend (A), wherein 100.0 wt.-% of themixed-plastic-polyethylene primary blend (A) originates frompost-consumer waste having a limonene content of from 0.10 to 500 ppm;and wherein the mixed-plastic-polyethylene primary recycling blend (A)has a melt flow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.4 to 1.3g/10 min, a density of from 945 to 990 kg/m³; and a content of unitsderived from ethylene of 70.0 to 95.0 wt.-% as determined byquantitative ¹³C{¹H} NMR, b. 25.0 to 88.0 wt.-% of a secondary component(B) being a first virgin high-density polyethylene (HDPE1) optionallyblended with carbon black, the secondary component (B) having a meltflow rate (ISO 1133, 2.16 kg, 190° C.) of from 0.2 to 0.6 g/10 min; adensity of from 955 to 970 kg/m³; a shear thinning index SHI_(2.7/210)of 15 to 30; a polydispersity index from 1.6 to 2.2 s⁻¹ as obtained fromrheological measurement; optionally a carbon black content of 1.5 to 3.0wt.-% with respect to the secondary component (B); and a limonenecontent below 0.10 ppm, c. 2.0 to 20.0 wt.-% of a second virginhigh-density polyethylene (C) having a melt flow rate (ISO 1133, 5.0 kg,190° C.) of from 0.10 to 0.5 g/10 min; a density from 945 to 965 kg/m³;a polydispersity index from 2.2 to 4.0 s⁻¹ as obtained from rheologicalmeasurement; and a limonene content below 0.10 ppm.
 2. Amixed-plastic-polyethylene composition according to claim 1, having adensity of from 959 to 966 kg/m³; the mixed-plastic-polyethylenecomposition.
 3. The mixed-plastic-polyethylene composition of claim 1comprising carbon black in an amount of 1.0 to 3.0 wt.-% with respect tothe total of the mixed-plastic-polyethylene composition.
 4. Themixed-plastic-polyethylene composition according to claim 1 comprisingone or more in any combination of: a total amount of units having 3carbon atoms as isolated peaks in the NMR spectrum (isolated C3 units)of from 0.00 wt.-% to 0.12 wt.-%; a total amount of units having 6carbon atoms (C6 units) of from 0.00 wt.-% to 0.50 wt.-%; a total amountof units having 7 carbon atoms (C7 units) of from 0.00 wt.-% to 0.10wt.-%; wherein the total amounts of isolated C3 units, C4 units, C6units, C7 units are based on the total weight amount of monomer units inthe composition and are measured or calculated according to quantitative¹³C{¹H} NMR measurement.
 5. (canceled)
 6. The mixed-plastic-polyethylenecomposition according to claim 1, wherein the mixed-plastic-polyethyleneprimary recycling blend (A) has an ESCR (Bell test failure time) of lessthan 1000 hours; and optionally includes TiO₂ in an amount of up to 3.0wt.-% with respect to mixed-plastic-polyethylene primary recycling blend(A).
 7. The mixed-plastic-polyethylene composition according to claim 1,wherein the secondary component (B) has an ESCR (Bell test failure time)of at least 2500 hours.
 8. The mixed-plastic-polyethylene compositionaccording to claim 1, wherein the second virgin high-densitypolyethylene (C) has: i. a melt flow rate (ISO 1133, 21.6 kg, 190° C.)of from 5.0 to 12.0 g/10 min; and/or ii. a comonomer content in therange from 1.5 to 3.0 wt.-%, wherein the comonomer is selected fromC(3-8) alpha-olefins.
 9. The mixed-plastic-polyethylene compositionaccording to claim 1, wherein the composition has an ESCR (Bell testfailure time) of at least 1000 hours.
 10. The mixed-plastic-polyethylenecomposition according to claim 1, wherein the impact strength at 23° C.(according to ISO 179-1 eA) is from 3.0 to 15.0 kJ/m² and/or wherein theimpact strength at 0° C. (according to ISO 179-1 eA) is from 2.5 to 10.0kJ/m².
 11. The mixed-plastic-polyethylene composition according to anyone of the preceding claims, wherein the strain hardening modulus (SHmodulus) is from 15.0 to 25.0 MPa.
 12. The mixed-plastic-polyethylenecomposition according to claim 1, having i. a melt flow rate (ISO 1133,2.16 kg, 190° C.) of from 0.2 to 0.6 g/10 min, and/or ii. a melt flowrate (ISO 1133, 5 kg, 190° C.) of from 1.2 to 2.2 g/10 min, and/or iii.a melt flow rate (ISO 1133, 21 kg, 190° C.) of from 30.0 to 50.0 g/10min.
 13. The mixed-plastic-polyethylene composition according to claim1, wherein the SHI_(2.7/210) is between 35.0 and 50.0.
 14. Themixed-plastic-polyethylene composition according to claim 1, wherein thecomposition is characterized in that a compression moulded plaque madefrom the composition having 1 mm thickness has a tear resistance of atleast 22.0 N/mm and optionally up to 30.0 N/mm.
 15. An articlecomprising the mixed-plastic-polyethylene composition according to claim1, wherein the article is a cable jacket.
 16. A process for preparingthe mixed-plastic-polyethylene composition according to claim 1,comprising: a. providing a mixed-plastic-polyethylene primary recyclingblend (A) in an amount of 10.0 to 70.0 wt.-% based on the overall weightof the composition, wherein 100.0 wt.-% of themixed-plastic-polyethylene primary blend (A) originates frompost-consumer waste having a limonene content of from 0.10 to 500 ppmand wherein the mixed-plastic-polyethylene primary blend has a melt flowrate (ISO 1133, 2.16 kg, 190° C.) of from 0.4 to 1.3 g/10 min: a densityof from 945 to 990 kg/m³; and a content of units derived from ethyleneof 70.0 to 95.0 wt.-% as determined by quantitative ¹³C{¹H}-NMR; b.providing a secondary component (B) being a first virgin high-densitypolyethylene (HDPE1) optionally blended with carbon black, in an amountof 25.0 to 88.0 wt.-% based on the overall weight of the composition,the secondary component (B) having a melt flow rate (ISO 1133, 2.16 kg,190° C.) of from from 0.2 to 0.6 g/10 min; a density of from 955 to 970kg/m³, a shear thinning index SHI_(2.7/210) of 15 to 30 a polydispersityindex from 1.6 to 2.2 s⁻¹ as obtained from rheological measurement,optionally a carbon black content of 1.5 to 3.0 wt.-% with respect tothe secondary component (B); and a limonene content below 0.10 ppm. c.providing a second virgin high-density polyethylene (C) in an amount of2.0 to 20.0 wt.-%, based on the overall weight of the composition, thesecond virgin high-density polyethylene having a melt flow rate (ISO1133, 5.0 kg, 190° C.) of from 0.10 to 0.5 g/10 min; a density from 945to 965 kg/m³, polydispersity index from 2.2 to 4.0 s⁻¹ as obtained fromrheological measurement; and a limonene content below 0.10 ppm d.melting and mixing a blend of mixed-plastic-polyethylene primary blend(A), the secondary component (B) and the second virgin high-densitypolyethylene (C) in an extruder, optionally a twin screw extruder, ande. optionally pelletizing the obtained mixed-plastic-polyethylenecomposition.